A communication arrangement for use by a single user or by a group of users sharing the same location for communicating with one or more remote users or groups of users may be provided as a combination of separate components, interconnected by electrical connections such as electrical wiring. Such a communication arrangement may be referred to as a distributed communication arrangement as opposed to an integrated communication arrangement hosting all components of the communication arrangement in a single device.
FIG. 1 schematically illustrates a communication arrangement 100 as an example of a distributed communication arrangement. The communication arrangement 100 comprises a control unit 110 and one or more radio units 140-i (representation in the illustration of FIG. 1 by radio units 140-1 and 140-2). Each of the radio units 140-i is coupled to the control unit 110 by respective electrical wiring 120-i. The connections between the components are, typically, provided using electrical cables that are detachably connectable to the control unit 110 and to the radio units 140-i. The radio units 140-i are operated as professional mobile radios (PMR) known in the art, each of the radio units 140-i arranged to enable point-to-point or point-to-multipoint communication between the respective radio unit 140-i of the communication arrangement 100 and one or more corresponding remote radio units. The control unit 110 is provided with audio input means (e.g. a microphone provided in or connected to the control unit 110) for receiving audio input from the user of the communication arrangement 100 and with audio output means (e.g. one or more loudspeakers provided in or connected to the control unit 110) for reproducing audio to the user of the communication arrangement 100. The control unit 110 is further provided with an user interface that enables the user of the communication arrangement 100 to control audio communication with other users, e.g. by using the push-to-talk (PTT) method known in the art, employing the radio unit 140-i of his/her choice. Hence, the electrical wirings 120-i of the communication arrangement 120-i carry audio signals between the control unit 110 and the radio units 140-i, as well as control signals from the control unit 110 to the radio units 140-i.
Applying a distributed communication arrangement, such as the communication arrangement 100, instead of an integrated one arrangement enables flexibility in selecting the components, such as audio input/output means, radio units (140-i) and control units (110) of desired type and characteristics to meet the requirements of a desired usage scenario. Moreover, the distributed approach makes replacing a component of the communication arrangement with a new one (e.g. due to damage or malfunction) a straightforward task, while at the same time it enables the user also to reconfigure the communication arrangement 100 by connecting only the radio unit(s) 140-i that are currently needed. Yet further, the distributed approach contributes to improved usability of the communication arrangement by enabling the user arranging (or wearing) the components in positions that facilitate ease of use and good performance in usage conditions that involve extensive user activity and/or mobility, as well as easy and reliable hands-free operation. To this end, the components of a distributed communication arrangement are typically provided as wearable components or components that can be otherwise mounted to the clothes or other gear worn or carried by the user of the communication arrangement or that can be mounted to fixed structures in the location of the user. Such distributed communication arrangements are typically applied in professional use where performance requirements for the communication arrangement are high and where easy and reliable ‘hands-free’ operation of the communication arrangement plays an important role. Such usage scenarios include military use (both in combat and training conditions), as well as use e.g. by the police, by firefighters, by construction workers, etc.
Designing a distributed communication arrangement comprising multiple components for professional use, where the components typically originate from different manufacturers, requires careful selection, configuration and testing of the components of the arrangement as well as the arrangement as a whole. Due to electrical connection between the components, it is typically important to take measures that ensure electrical compatibility between the components of the arrangement in order to guarantee performance fulfilling requirements related to the quality, reliability and safety of the communication. In particular, the communication arrangement may need to show compliance to regulations regarding electromagnetic compatibility (EMC) and/or intrinsic safety (IS) in order to certify the communication arrangement as applicable for certain professional use.
Regarding EMC, examples of EMC standards and regulations include the ones specified in the Directive 2004/108/EC of the European Parliament and of the Council of 15 Dec. 2004. Regarding IS, examples of IS regulations include the Directive 94/9/EC of the European Parliament and the Council of 23 Mar. 1994 for equipment and protective systems intended for use in potentially explosive atmospheres (ATEX), International Electrotechnical Commission System for Certification to Standards Relating to Equipment for use in Explosive Atmospheres (IECEx system), as well as IS certifications provided by Factory Mutual (FM) Research Corporation and Underwriters Laboratory (UL) (in the United States). Examples of FM standards in this regard include FM 3600 (Approval Standard for Electrical Equipment for Use in Hazardous (Classified) Locations—General Requirements, Class Number 3600, December 2011) and FM 3610 (Approval Standard for Intrinsically Safe Apparatus and Associated Apparatus for Use in Class I, II, and III, Division 1, Hazardous (Classified) Locations, Class Number 3610, January 2010). Examples of UL standards in this regard include UL 913 (Intrinsically Safe Apparatus and Associated Apparatus for Use in Class I, II, and III, Division 1, Hazardous (Classified) Locations, Jul. 29, 1988) UL 60079-0 (Explosive Atmospheres—Part 0: Equipment—General Requirements, ed.5, Oct. 21, 2009) ad UL 60079-11 (Explosive Atmospheres—Part 11: Equipment Protection by Intrinsic Safety ‘I’, ed. 5, Sep. 30, 2009).
Conformance to desired performance requirements and regulations related to EMC and/or IS are likely to further complicate the process of matching the components of the communication system to operate together, possibly leading to sub-optimal performance of some components of the communication arrangement or even compromised quality of communication due to ill-matching or even conflicting requirements of the components employed in the arrangement. In particular, modifying such a distributed communication arrangement e.g. by introducing an additional component, removing one of the existing components and/or replacing one of the existing components with a new one is likely to require re-configuration of the components of the of the communication arrangement and/or re-configuration of the communication system as a whole in order to guarantee desired quality and reliability of communication—as well as re-testing of conformance to relevant EMC and/or IS regulations. Such re-configuration and re-testing may be time-consuming, inconvenient and in many cases also costly.